Communication apparatus and method using random access procedure

Abstract

User equipment (UE) that includes a processor and that executes a random access procedure with a base station (E-UTRAN Node B (eNodeB), also known as Evolved Node B) is provided. The UE can at least temporarily be embodied by the processor. The UE may comprise: a determination unit for determining a message size that can be transmitted and that corresponds to a physical random access channel according to an assigned communication method with the base station; a calculation unit for configuring a message to correspond to the message size and for respectively calculating a preamble index and at least one message index from the message; and an encoder for providing respective encoding of the preamble index and the at least one message index, and transmitting the same to the base station.

What is claimed is: 
     
       1. A terminal comprising a processor and that is to perform a random access procedure with a base station, the terminal comprising:
 a processor configured to determine a transmittable message size corresponding to a physical random access channel based on a predetermined communication scheme with the base station; 
 a calculator configured to set a message to correspond to the message size, and to calculate each of a preamble index and at least one message index from the message; and 
 an encoder configured to encode each of the preamble index and the at least one message index, and to transmit the same to the base station, wherein the encoder is further configured to generate each of a preamble sequence acquired by cyclic shifting a Zadoff-Chu sequence corresponding to a preamble root index by a constant value corresponding to the preamble index and a message sequence acquired by cyclic shifting a Zadoff-Chu sequence corresponding to each of the at least one message root index by a sum of the constant value corresponding to the preamble index and each of the at least one message index, and to transmit the generated preamble sequence and message sequence to the base station. 
 
     
     
       2. The terminal of  claim 1 , wherein the processor is configured to determine the transmittable message size based on a Zadoff-Chu sequence length corresponding to the predetermined communication scheme, a number of preamble sequences, and a number of message root index functions. 
     
     
       3. The terminal of  claim 1 , wherein the calculator is configured to calculate at least one message root index different from a preamble root index using each of at least one message root index function that uses the preamble index as an independent variable. 
     
     
       4. The terminal of  claim 1 , wherein the calculator is configured to iteratively extract at least one message bitstream corresponding to each of the at least one message index from a start bit of the set message, and to extract a preamble bitstream from the remaining message. 
     
     
       5. The terminal of  claim 1 , wherein, when transmitting a message increased to be greater than a Zadoff-Chu sequence length corresponding to the predetermined communication scheme, the processor is configured to transmit the increased message using a plurality of subframes corresponding to the physical random access channel. 
     
     
       6. The terminal of  claim 1 , further comprising:
 a selector configured to select one of a preamble transmission mode and a simultaneous message transmission mode, 
 wherein when the selector selects the preamble transmission mode, the encoder is configured to encode the preamble index and to transmit the encoded preamble index to the base station. 
 
     
     
       7. A base station comprising a processor and that is to perform a random access procedure with a terminal, the base station comprising:
 the processor comprising a calculator configured to calculate a received preamble index using a sequence received from the terminal and a Zadoff-Chu sequence associated with a preamble; 
 the processor further configured to determine whether a preamble collision is present using a Zadoff-Chu sequence associated with a message root index that is determined based on the preamble index, 
 a decoder configured to decode a message transmitted from the terminal through the random access procedure using the preamble index and a message index, 
 wherein the processor is configured to calculate, when it is determined that the preamble collision is absent, the message index using the received sequence and the Zadoff-Chu sequence associated with the message root index. 
 
     
     
       8. The base station of  claim 7 , wherein the processor is configured to calculate a correlation value between the received sequence and the Zadoff-Chu sequence associated with the message root index, and to determine that the preamble collision is present when at least two peaks of the correlation value exceed a preset threshold. 
     
     
       9. A base station comprising a processor and that is to perform a random access procedure with a terminal, the base station comprising:
 a calculator configured to calculate a correlation value corresponding to a preamble index and a correlation value corresponding to each of at least one message index using a sequence received from the terminal; 
 a detector configured to detect each of the preamble index and the at least one message index based on the correlation value corresponding to the preamble index and the correlation value corresponding to each of the at least one message index, and 
 a decoder configured to decode a message transmitted from the terminal through the random access procedure using the at least one message index and the preamble index, 
 wherein the decoder is configured to determine, as the operation mode of the terminal, at least one of a first mode for transmitting a subsequent message using a random access resource, a second mode for transmitting the message through a unit frame and terminating the transmission, and a third mode for transmitting the subsequent message through an additional frame. 
 
     
     
       10. The base station of  claim 9 , wherein the calculator is configured to calculate at least one message root index that is determined based on the preamble index using at least one message index function, and to calculate the correlation value corresponding to each of the at least one message index using a Zadoff-Chu sequence corresponding to the at least one message root index. 
     
     
       11. The base station of  claim 9 , wherein the detector is configured to detect each of the at least one message index by comparing a location number corresponding to a peak of the correlation value corresponding to the preamble index to a location number corresponding to a peak of the correlation value corresponding to each of the at least one message index. 
     
     
       12. The base station of  claim 9 , wherein the decoder is configured to identify a predetermined prefix bit from the decoded message, and to determine an operation mode of the terminal based on the prefix bit. 
     
     
       13. The base station of  claim 9 , wherein, when the operation mode is the first mode, the decoded message includes a scheduling request that includes resource block size information used to transmit the subsequent message. 
     
     
       14. The base station of  claim 9 , wherein, when the operation mode is the third mode, the decoder is configured to determine the message as a portion of an entire message transmitted from the terminal and to merge a subsequent message decoded from the additional frame.